But when the final syllable of the first word was accented, its ‑s combined with an initial tenuis, which thus became a spirant. For this reason we have the spirant mutation of a tenuis after Ml. W. ɥ ‘her’ (now written ei) < *esi̯ā́s = Skr. asyā́ḥ ‘her’; tri ‘three’ < Brit. *trei̯és (for *tréi̯es would have given *trydd); a ‘with’ and a ‘and’ < Brit. *aggós § 213 iii (1), § 222 i (3). On the mutation after ni, see § 217 iv (1); after chwe § 108 iii.
tair and pedair had the same accentuation, and in Bret. ter, peder, and also pevar (= pedwar), cause the spirant mutation. The radical has been substituted in W., as in the majority of cases where the spirant occurred from the above cause.
(4) After final ‑s initial l and r were unvoiced; cf. sl- > ll‑; sr- > rh‑, § 95 i; but between vowels l and r underwent no change. Thus we have ll and rh now in those positions where the radical occurs of the consonants mentioned in (1) above, and l and r in those positions where the said consonants are softened. Welsh grammarians therefore speak of ll, rh as “radical”, and l, r as “mutated” consonants. Though the reverse is historically the case, it is convenient to retain the old terminology in dealing with the interchange of the sounds in the present language.
Note. The term “soft mutation”, first applied to the change where it occurred initially, is due to Dr. Davies, who called it “forma mollis” D. 26. It has also been called “vocal” and “middle”. The latter name, used by Rowland, owes its origin to the term “forma media” used by Davies as a name for the change of the tenues to the mediae; as applied to the six others it is meaningless. Continental scholars use “Lenition” as a term embracing the Welsh “soft mutation” and the corresponding Irish “aspiration”.
(5) Lat. sp, st, sc remained, as Ml. W. yspeil < spolium § 69 iv (1), ystyr < historia ib., escyn < ascend‑. An explosive before the group dropped in W., as in estron < extrāneus; so after the loss of an intervening vowel, as W. esgob < episcopus, W. esgud ‘active’ < exsecūtus. See further § 111 vi (2). Except where c dropped as above Lat. x > i̯s, 108 v.
ii. (1) Medially between vowels ᵹ, the soft mutation of g, disappeared completely after the O. W. period; as in saeth i (1);—maes < *maᵹes § 29 ii (2): Gaul. ‑magus;—teyrn ‘ruler’ < *tyyrn
